package com.hou.practice.leetcode.mainofleetcode0;

/**
 * @author H
 * @create 2021-07-21 20:03
 */
public class Solution097 {

    public boolean isInterleave(String s1, String s2, String s3) {
        int m = s1.length(), n = s2.length();

        if (s3.length() != m + n) {
            return false;
        }
        // 动态规划，dp[i,j]表示s1前i字符能与s2前j字符组成s3前i+j个字符；
        boolean[][] dp = new boolean[m+1][n+1];
        dp[0][0] = true;
        // 不相符直接终止
        for (int i = 1; i <= m && s1.charAt(i-1) == s3.charAt(i-1); i++) {
            dp[i][0] = true;
        }
        // 不相符直接终止
        for (int j = 1; j <= n && s2.charAt(j-1) == s3.charAt(j-1); j++) {
            dp[0][j] = true;
        }
        for (int i = 1; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                dp[i][j] = (dp[i - 1][j] && s3.charAt(i + j - 1) == s1.charAt(i - 1))
                        || (dp[i][j - 1] && s3.charAt(i + j - 1) == s2.charAt(j - 1));
            }
        }
        return dp[m][n];
    }
}
